JSON Lines is how logs, exports and LLM fine-tuning datasets travel. Convert a .jsonl file into a proper JSON array to inspect it, or flatten an array back into one record per line — with bad lines reported by line number.
⌘/Ctrl + Enter runs it again. Everything happens in this browser — nothing is uploaded.
JSON Lines is how logs, data exports and LLM fine-tuning datasets travel: one JSON document per line, appendable and streamable. It is also awkward to inspect, because no ordinary JSON tool will parse the file as a whole. This converts a .jsonl file into a proper array you can read, search and feed to the other tools here, and flattens an array back to one record per line.
Practically none — both mean one JSON value per line, separated by newlines. The names are used interchangeably, and this tool reads and writes both.
Yes. By default it refuses and tells you which lines are bad; tick "Skip invalid lines" and it converts everything else, reporting how many it skipped.
Yes — those are JSONL. Convert to an array to inspect or edit the set, then convert back to JSONL for upload.